Halogen cycle incandescent lamps

ABSTRACT

A halogen lamp exhibiting a good regenerative halogen cycle is sealed with an inert or nitrogen gas, chlorine and fluorine, preferably, in the form of a hydrocarbon halide. Quantities of chlorine and fluorine are respectively from 0.05 X 10 6 to 1.00 X 10 6 gram atoms of chlorine and from 0.05 X 10 6 to 1.50 X 10 6 gram atoms of fluorine per cubic centimeter of the inner volume of the lamp.

United States Patent Inventors Keiichi Sugano;

Takashi Ohmori; Yoji Yuge, all of Yokohama-shi, Japan App1.No. 887,610

Filed Dec. 23, 1969 Patented Nov. 9, 1971 Assignee Tokyo Shibaura Electric Co., Ltd. Kawasaki-shi, Japan Priority Dec. 27,1968

Japan 43/95779 HALOGEN CYCLE INCANDESCENT LAMPS 8 Clalms, 2 Drnwlng Figs.

11.8. C1 313/222, 313/223 Int. Cl H011: 1/50 Field 01 Search 313/222, 223

[56] References Cited UNlTED STATES PATENTS 1,925,857 9/1933 Van Liempt 313/222 X 3,022,439 2/1962 Cooper, Jr. et a1. 313/222 3,453,476 7/1969 English 313/222 X 3,475,649 10/1969 Nameda et a1 313/223 3,484,146 12/1969 Meijer et a1 313/222 UX Primary Examiner Roy Lake Assistant Examiner- Palmer C. Demeo AlmrneyGeorge B. Oujevolk ABSTRACT: A halogen lamp exhibiting a good regenerative halogen cycle is sealed with an inert or nitrogen gas, chlorine and fluorine, preferably, in the form ofa hydrocarbon halide. Quantities of chlorine and fluorine are respectively from 0.05 X10 to 1.00 XlO' gram atoms of chlorine and from 0.05 XlO' to 1.50 10 gram atoms of fluorine per cubic centimeter of the inner volume of the lamp,

HALOGEN CYCLE INCANDESCENT LAMPS This invention relates to a lamp and more particularly to an electric halogen lamp.

Various types of halogen electric lamps have been proposed wherein halogens such as iodine (l), bromine (Br), chlorine (Cl) and iodine monobromide (IBr) or hydrocarbon halides such as methyl bromide (CH Br), methylene chloride (Cl-l Cl are sealed in glass bulbs together with nitrogen or inert gas so as to effect a regenerative halogen cycle by these halogens. However, such prior art lamps have the following defects.

More particularly, halogens are very harmful even'when they are present in a very small quantity and their chemical affinity toward other substances is very strong. For this reason, it is highly desirable to pay minute care in the manufacture of such halogen lamps so as not to endanger workmen. Especially, as these characteristics are remarkable in iodine, bromine and iodine bromide, not only do they require careful handling but also they react and corrode sealing members of metal or rubber. Moreover, these characteristics render incomplete the regenerative halogen cycle during operation of the lamps. Thus, for example, in electric lamps wherein the operating temperature of their bulb wall exceeds 250 C., control of the quantity of halogens sealed therein is difficult. Thus, where the quantity of halogens is too small, blackening phenomenon of the wall will result whereas excessive quantity will result in the corrosion of portions in the bulbs of relatively low temperature due to halogen atoms such as the anchors which support the filament or the joints between the filament and the anchors. ln halogen lamps having two pins for use in cinematographs, in addition to the above-described problems of corrosion and blackening the electric insulation between inner legs of lead-in wires each connected to said pins deteriorates thus causing arcing therebetween so that it is necessary to seal in the halogen gas together with a specially mixed carrier gas, for instance consisting of 86 percent, by weight, of argon and l4 percent, by weight, of nitrogen in order to prevent the arcing.

it is an object of this invention to provide halogen lamps of high utility which are substantially free from the problems of blackening and corrosion and can provide satisfactory regenerative halogen cycle. In accordance with this invention, chlorine and fluorine are used as the halogen to be sealed in the bulb together with a nitrogen gas and/or an inert gas such as argon gas, said chlorine and fluorine being used in an amount of 0.05 10- to l.00 l gram atoms per cubic centimeter and 0.05 to l.50 10- gram atoms per cubic centimeter, respectively of the inner volume ofthe bulb.

According to the other aspect of this invention, chlorine, fluorine and carbon are used in the form of organic compounds so that in addition to the above-described merit of eliminating the problem of blackening and corrosion, such organic compounds are advantageous in that they are colorless and harmless to human bodies.

This invention can be more fully understood from the following detailed description when taken in connection with reference to the accompanying drawing, in which:

FIG. 1 is a front elevation ofa halogen lamp embodying this invention; and

FIG. 2 shows a perspective view of a modified embodiment of this invention.

As above described, in accordance with this invention 0.05 X l0bh6 to l.0O 10* gram atoms of chlorine per cubic centimeter and 0.05 10- to l.50 10- gram atoms of fluorine per cubic centimeter of the inner volume of the bulb are used together with nitrogen and/or inert gas. However, it is advantageous to use chlorine and fluorine in combination with carbon. Hydrocarbon halides, or compounds of fluorine, chlorine and carbon, for example,

diclorodifluoromethane (CFgCig) or 1,2-dichloro-l,l,2,2-'

tetrafluoroethane (QCI F are colorless so that bulbs filled with these hydrocarbon halides are free from absorption of light which is inherent to a conventional iodine lamp and have extremely high luminous efficiency. In

addition these hydrocarbon halides are not harmful and can be handled safely. In addition, since they are extremely stable chemically at room temperature they never corrode common metals, thus ensuring satisfactory maintenance of the gas sealing apparatus. Finally, it is to be particularly pointed out that these hydrocarbon halides do not undergo decomposition unless they are heated to temperatures exceeding 500 to 600 C. Thus portions of the lamps at relatively low temperature, such as supports and anchors would not be corroded. Only at portions of the lamp which attain high temperature during operation of the lamp, for example, the central portion of the tungsten filament, tungsten fluorine and chlorine produced by decomposition undergo satisfactory regenerative halogen cycle thus eliminating the phenomenon of blackening.

Referring now to FIG. 1 which illustrates one embodiment of the halogen lamp of this invention and having conventional appearance, briefly, the lamp comprises a transparent glass cylindrical bulb or envelope 1 containing a transverse filament of a tungsten coil 2. Opposite ends of the filament are connected to metal foils 4 embedded in a squeezed portion of the bulb 1 via lead wires 3, the foils being connected to terminal pins 5 protruding from the base of the lamp. The bulb is sealed with 0.l0 l0" mol of dichlorodifluoromethane (CF Cl per 1 cubic centimeter of the inner volume of the bulb and argon gas under a pressure of 600 to 700 mm. Hg.

After operation of 70 hours, lamps sealed with these gases and having a rating of 24 v., 150 w., 33 lm./w. did not show any tendency of wall blackening and corrosion of low temperature portions and manifested satisfactory regenerative halogen cycle.

Gases of the following compositions were filled in lamps of the above-described a sulm were tested. 0.l l

and c Quantity scaled Lamps sealed with CF CI and C Cl F showed no tendency of blackening whereas lamps containing Cl-lF Cl or a compound containing hydrogen in addition to chlorine and fluorine manifested blackening. ln this case, however, it was found that by selecting the molar ratio of fluorine and hydrogen in a range of 4:1 to 5:1 the phenomenon of blackening can be avoided. In other words, in this invention by suitable selection of the quantity of hydrogen, it may be present with other elements.

On the other hand, in the above-described lamps, iodine bromide was used as the halogen gas. The results of tests showed that in conventional lamps arcings were noted and the filament coil was broken at their ends whereas such difficulties were not noted in the lamps of this invention.

A modified embodiment having a rating of v., 500 w. shown in FIG. 2 comprises a transparent cylindrical glass 10 containing a tungsten coil filament 11 supported by a plurality of anchors 12 at spaced-apart points along the length thereof such that the filament 11 extends along the longitudinal axis of the bulb. On the opposite ends of the bulb are formed pinched portions 13 in which molybdenum foils 14 are hermetically sealed. Opposite ends of the filament coil 11 are connected to respective foils 14 through lead wires 15 and outer terminal pins 16 are connected to foils. Within the tube is sealed the atmosphere of the above described embodiment or a mixture of argon and CF Cl gas.

Lamps of this embodiment were also subjected to similar continuous life test under the same rated voltage. After l0 ln assembling grid electrode 7 shown in FIG. 4a with the anode electrode shown in FIG. 5, projections 14' are fitted in guide openings 14 is above described to bring grid electrode 7 close to the insulating substrate 2 thus providing an assembly as shown in FIG. 6. Filament 6 is then mounted to extend in front of the assembly and lead wires are connected to respective electrodes. The assembly is then sealed in the glass envelope 9 to complete the fluorescent tube shown in FIG. 3.

As above described the function of a control grid that controls the divergence and flow of electrons and that of a screen grid electrode that collects the substances evaporated from fluorescent anode segments and secondary electrons emanated therefrom are provided by a single grid electrode. As a result, the number of electrodes is decreased by one thus providing an inexpensive fluorescent display tube wherein electrodes can be assembled readily.

The grid electrode employed in this invention has a window of a configuration of a pattern comprised by all fluorescent segments on an insulating substrate and a mesh is formed in the window. Furthermore, different from a prior screen grid, as there is no bridge in the window corresponding to and aligning with the insulating bridges between segments on the insulating substrate, it is not necessary to take care to align the window with the insulating bridge on the insulating substrate, thus rendering easy assembling. This construction also eliminates the provision of a control grid between the screen grid and the filament which was essential to the prior construction so that it becomes possible to dispose the filament closer to the anode electrode thus flattening and miniaturizing the display tube. The cutoff characteristics of the novel display tube has been improved about 30 percent over the prior fluorescent display tube.

What is claimed is:

1. A fluorescent display tube comprising an evacuated sealed envelope, an insulating substrate within said envelope, an anode electrode including a plurality of fluorescent anode segments adapted to form characters, said anode segments being mounted on said insulating substrate and insulated from each other, a single grid electrode disposed close to said anode segments, and a cathode filament extending in front of said grid electrode, said grid electrode being provided with a window common to the region of a pattern formed by said plurality of fluorescent anode segments, said window being provided with an electroconductive mesh.

2. The fluorescent display tube according to claim I wherein said grid electrode comprises a metal plate provided with a window of a configuration corresponding to a pattern formed by all segments of a character to be displayed and a metal mesh provided for said window and wherein said anode comprises a plurality of fluorescent anode segments embedded in said insulating substrate and insulated from each other, said anode segments being arranged to be combined to display a desired character or digit and wherein said grid electrode and said anode electrode are assembled together.

3. The fluorescent display tube according to claim I wherein said grid electrode and said substrate are connected together by means of interfitting projections and openings. 

2. A halogen lamp according to claim 1 wherein said second gas further contains carbon.
 3. A halogen lamp according to claim 1 wherein said second gas is a hydrocarbon halide containing chlorine and fluorine.
 4. A halogen lamp according to claim 3 wherein said second gas is selected from the group consisting of monochlorodifluoromethane and dichlorotetrafluoroethane.
 5. A halogen lamp according to claim 3 wherein said hydrocarbon halide further contains hydrogen, the molar ratio of halogen to hydrogen being 4:1 to 5:1.
 6. A halogen lamp according to claim 5 wherein said hydrocarbon halide is monochlorodifluoromethane.
 7. A halogen lamp comprising a transparent bulb, a tungsten coil filament mounted in said bulb, a pair of conductive foils sealed in the opposite ends of said bulb, a pair of condUctors interconnecting opposite ends of said filament and said foils, outer terminal pins respectively connected to said foils and extending outwardly through the ends of said bulb, argon gas and a gas mixture containing chlorine and fluorine, the quantities of said chlorine and fluorine being from 0.05 X 10 6 to 1.00 X 10 6 gram atoms of chlorine and from 0.05 X 10 6 to 1.50 X 10 6 gram atoms of fluorine per cubic centimeter of the inner volume of said bulb.
 8. A halogen lamp according to claim 7 wherein said filament is mounted along the longitudinal axis of said bulb and supported by a plurality of spaced-apart anchors at a plurality of points along said filaments. 